Television receiving set



July 4, 1939. P. M. G. fvuLou wnmvxslou RECEIVING saw Filed Nov. 6, 1936INVENTOR P/ERRE MAR/AF Mix/EL T0010 BY #g 4 1 MW ATTORNEY Patented July4, 1939 vireo STATES PATENT, OFFICE TELEVISION RECEIVING SET poration ofDelaware Application November 6, 1936, Serial No. 109,476 In FranceNovember 6, 1935 2 Claims.

The television receiving screens which actually consist of thefluorescent wall of cathode-ray oscillographs are always very small. Inorder to be able to follow comfortably the transmitted picture, it isnecessary to increase that picture and to move it away from theobserver. It has been already proposed to place magnifying glasses infront of the oscillograph screen, but the effect obtained in this manneris always restricted and the screen can be observed only by a very smallnumber of spectators. It has been also proposed to projectthe real imageof the screen on a diffusing surface, but there the lack in luminosityhas interfered with progress.

The present invention constitutes a new solution of that problem, andpermits, starting from a cathode-ray oscillograph, the luminous part ofwhich amounts to a few square centimeters, to obtain an image, theapparent dimensions of '20 which amount to several meters, so that theobserver can enjoy them without. effort in his visual accommodation. Themagnification is obtained either by means of suitably-built concavemirrors that are especially arranged, or by means 5 of convex glassesthat are integral with a reservoir containing a liquid, the index ofrefraction of which differs from that of the atmosphere.

In both cases, the observer examines a virtual image at a relativelysmall angle, which image is nearly always located at an infinitedistance. The attached figures, which are given 'by way of non-limitingexamples, show the importance of the invention and representconstructive arrangements which have been worked out for itselaboration.

Fig. -1 represents a concave mirror, which permits obtaining a veryenlarged virtual image of the screen and of producing at the same timean illusion of relief.

Fig. 2 shows how the utilization of an optical system that produces anenlarged vertical image constitutes the solution of the problem ofbuilding -a very large apparent screen, so that the spectators may enjoythe showing of pictures,

,4'5'the size of which is not out" of proportion with the intensity ofsound furnished by the loud speaker.

' ,As Fig. l-represents, the. cathode-ray oscillograph is arrangedpreferably vertically.

50 bodyof the oscillograph 2- is mounted on a housing, the-electron gunI beingplaced at the lower part and the fluorescing screen 5 to theupper .part. A plane mirror 3 sends light rays to the I concave mirror 4and then in the direction of the 55 observefs eyes. The latter examinesthrough The an opening 18 the virtual image 6 which is very enlarged andwhich takes the place of the small screen 5. This image MN reproducesfaithfully the image MNn, but seems to be located several meters back ofthe screen, although its 5 luminosity remains the same. An auxiliaryscreen 9-40 limits the apparent dimensions of the concave mirror. Byvirtue of the presence of the screens which are placed one behind theother (I-8 and 9-40), the image MN' seems 10 to be endowed with relief.The amplifier II is mounted at the lower part of the cabinet.

Fig. 2 represents another arrangement which permits building a lens ofconsiderable dimensions, which at the same time operates very 15economically.

It is known that the dimension of the lens must be very large so thatthe observer may occupy, in the room, any position. Themaking of lenseswith a diameter of 0.80 meter, for example, would 20 require a pricewhich could not be even approached.

The invention permits the economic realization of a lens by means of aliquid with a high index of refraction. The oscillograph 13 with itselec- 5 tron gun l2 and its screen I4 is arranged in front of themounting 22, in which are mounted a plane glass I6 and a curved glassIT. The interval between the plane glass and the convex glass is filledwith a liquid. Rubber sheets l8, I9 30 and 20 insure the hermetictightness of the device. The two glasses are fastened oneagainst theother by means of washers 2| and 22'which are tightened by means ofbolts 23. One can observe an enlarged virtualimage I4. 35

As liquid, one can use oil, for instance, paraffin oil, as well asVaseline oil, the index of refraction of which comes close to that ofglass, and which remains unchanged.

I claim: I 4o 1. A system to produce reflected representations ofelectro-optical images developed by an electron tube which comprises afirst reflecting elementadapted to receive the optical image from theelectron tube andto reflect the said image according to a firstpredetermined path of reflection, a second reflecting surface positionedin the path of the first reflection to direct the reflected image alonga second predetermined path of reflection, a cabinet having a viewingillumination external to the cabinet, and an image size masking meanspositioned intermediate the electron tube and the viewing window tolimit the apparent dimensions or the second reflecting element and toconfine the developed image to predetermined boundaries.

2. A system to produce reflected representations of electro-opticalimages developed by an electron tube which comprises a housing cabinet,an electronic scanning tube for producing electro-optical imagerepresentations, 9. first reflecting element supported within thecabinet and positioned to receive the optical image from the electrontube and to reflect the image according to a first predetermined path ofreflection, a concave reflecting surface supported within the cabinetand positioned in the path 01. the first reflection to direct thereflected image along a second predetermined path of reflection, saidconcave reflector being so located and positioned within the housingcabinet as to he completely shielded from external light except for theviewing direction thereof, said concave reflecting surface being adaptedto produce a. virtual image of the electro-optical image developedwithin the tube with the image apparently located rearwardly of thesurface of the concave reflecting surface, said housing cabinet having aviewing window located in alignment with the concave reflecting elementfor permitting observation of the produced virtual image, and an imagesize masking means positioned intermediate the electron tube and theviewing window to limit the apparent dimensions of the second reflectingelement and to confine the developed image to predetermined boundaries.

PIERRE MARIE GABRmL TOULON

